This will be only marginally cheaper than a full set. Spacebars cost 2.5 USD each, 1u keys about 0.6 USD each, 1.25 keys 1.5 USD each. The price of Alphas (1st group) plus modifiers and spacebars in the second group will be about 90 USD
Let's see, but a full key set would be over 130 USD and for sixty users the additional cost is paid for keys that will have no use at all, I would not consider that difference as marginal if I will save money I should pay for keys I have no use for. This set focused on users that not need full sets, while it covers all their needs, I'd say that is innovation.
Very recently I've seen full sets sold for 115 USD. And about two yes ago, triumph Adler reached 99 USD on massdrop. It even had custom colours.
Haha.
Simply, Normally MOQ will be increased, it lead to decrease the price. One step will be lead to decrease about 9~10%.
Let see....GMK MOQ is 150 / 250 / 500 / 1000 / 1500.
TA(only 121 keys) is maybe 500 MOQ ==> 99 USD
If 250 ==> 99 / 0.9 = 110USD
If 150 ==> 110 / 0.9 = 122USD
If TA was 140~150keys, maybe +15USD. (2 years ago)
Also your calculation is very simple. But calculation is not simple. We have to consider many thing as processing / Color(one tone or two tone or some novelty keys) / Size / side pad printing / LED keys(if added)New mold price (if used) / ETC..... Also exchange rate(Now EURO/USD = 1.2)
Normally 140~150keys with 250 MOQ is 130~140USD in many GBs. It means that if 150MOQ, maybe generally 140~150USD. (Not massdrop).
I am not sure but in my calculation, maybe only 60% set will be about 110 USD with 150MOQ, about 100 USD with 250 MOQ.
(In your calculation, you mention that 0.6 USD for 1U keys. So 40~50keys difference is about 30USD. So my calculation is not big difference)
I will try to discuss with GMK and it will be helpful to decrease the cost.